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Submarine hull

A light hull (casing in British usage) of a submarine is the outer non-watertight hull which provides a hydrodynamically efficient shape. The pressure hull is the inner hull of a submarine; this holds the difference between outside and inside pressure.

Submarine hull

Modern submarines are usually cigar-shaped. This design, already visible on very early submarines is called a "teardrop hull", and was patterned after the bodies of whales. It significantly reduces the hydrodynamic drag on the sub when submerged, but decreases the sea-keeping capabilities and increases the drag while surfaced.

History

The concept of an outer hydrodynamically streamlined light hull separated from the inner pressure hull was first introduced in the early pioneering submarine Ictineo I designed by the Catalan inventor Narcís Monturiol i Estarriol in 1859. However, when military submarines entered service in the early 1900s, the limitations of their propulsion systems forced them to operate on the surface most of the time; their hull designs were a compromise, with the outer hulls resembling a ship, allowing for good surface navigation, and a relatively streamlined superstructure to minimize drag under water. Because of the slow submerged speeds of these submarines, usually well below 10 knots (19km/h), the increased drag for underwater travel by the conventional ship like outer hull was considered acceptable. Only late in World War II, when technology enhancements allowed faster and longer submerged operations and increased surveillance by enemy aircraft forced submarines to spend most of their times below the surface, did hull designs become teardrop shaped again, to reduce drag and noise. On modern military submarines the outer hull (and sometimes also the propeller) is covered with a thick layer of special sound-absorbing rubber, or anechoic plating, to make the submarine more difficult to detect by active and passive SONAR.

History

Origins

Sage's intense interest in music began with cutting records at home as an adolescent.

Inspired by Jimi Hendrix, Sage soon picked up the guitar, and in 1971, at age 17, he played on an eponymous album by professional wrestler Beauregarde.

Foundation, early years

Sage founded the Wipers in Portland in 1977 along with drummer Henry and bassist Koupal, originally just as a recording project. The plan was to record 15 albums in 10 years without touring or promotion. Sage thought that the mystique built from the lack of playing traditional rock 'n' roll would make people listen to their recordings much deeper with only their imagination to go by. He thought it would be easy to avoid press, shows, pictures and interviews. He looked at music as art rather than entertainment; he thought music was personal to the listener rather than a commodity.

A wiper generally consists of a metal arm, pivoting at one end and with a long rubber blade attached to the other. The arm is powered by a motor, often an electric motor, although pneumatic power is also used in some vehicles. The blade is swung back and forth over the glass, pushing water or other precipitation from its surface. The speed is normally adjustable, with several continuous speeds and often one or more "intermittent" settings. Most automobiles use two synchronized radial type arms, while many commercial vehicles use one or more pantograph arms.

On some vehicles, a windshield washer system is also used. This system sprays water or an antifreeze window washer fluid at the windshield using several nozzles. The windshield washer system helps to remove dirt or dust from the windshield when it is used in concert with the wiper blades. When antifreeze windshield washer fluid is used, it can help the wipers to remove snow or ice. For winter conditions, some vehicles have additional heaters aimed at the windows or embedded heating wire in the glass. These defroster systems help to keep snow and ice from building up on the windshield. In rare cases, miniature wipers are installed on headlights.

Latest News for: hull wipers

The Freedom class resemble traditional Navy ships with steel hulls and aluminum superstructures, while the Independence-class ships have trimaran hulls made entirely of aluminum ... The ships aren’t called by their full names until they are commissioned to the Navy, but their hull numbers never change ... Louis (LCS 19) completed that step, and Thursday its hull was starting to look like something that could glide through water....